Iron bacteria are small living organisms that naturally occur in soil, shallow groundwater, and surface waters. These bacteria combine iron (or manganese) and oxygen to form deposits of "rust," bacterial cells, and a slimy material that sticks the bacteria to well pipes, pumps, and plumbing fixtures.

Iron bacteria can occur in various water sources, including private wells, public water supplies, and natural bodies of water. However, they are more commonly encountered in groundwater sources, particularly those with high levels of dissolved iron.

Iron bacteria form rust-colored slimy or stringy deposits in or on the surface of puddles or slow-moving water. They can also leave rust-colored stains on concrete, patios, sidewalks, and other hard surfaces. You may also see an oily sheen on the water's surface.